The UN secretary general, Kofi Annan, and the US secretary of state, Condoleezza at the Rome summit aimed at ending the conflict in Lebanon. Photograph: Sandro Pace/AP

The split within the international community over the Lebanon war was clearly exposed yesterday when the US and Britain combined at a Rome summit to block a move by European and Arab countries to demand an immediate ceasefire.

In a frenetic last 90 minutes of the summit, Condoleezza Rice, the US secretary of state, had to fend off a chorus of calls from foreign ministers demanding that she support a call for Israel and the Lebanese-based militia, Hizbullah, to declare a temporary truce. Her only ally at the conference was Margaret Beckett, the foreign secretary.

A US state department official travelling with Ms Rice denied the US had been isolated, a view disputed by other sources at the conference. A state department official said: "Whether we call [the ceasefire] immediate or urgent is semantics. We walked out of that room with the same sense of urgency [as others]."

The conference ended with a statement fudging the ceasefire issue, with participants expressing "their determination to work immediately to reach with the utmost urgency a ceasefire", but going on to incorporate Washington's insistence that any cessation of hostilities be "lasting, permanent and durable".

The conference in Rome's foreign ministry was also attended by the UN, Canada, Cyprus, Egypt, France, Germany, Greece, Jordan, Russia, Saudi Arabia, Spain, Turkey, the European Union and the World Bank, as well as representatives from Lebanon. Israel was not invited nor were Iran and Syria, both backers of Hizbullah.

The meeting was scheduled to last two-and-a-half hours but it overran by 90 minutes because of the row over a ceasefire.

A conference source said the focus of diplomatic activity would now shift to the UN in New York, but that substantive discussions on a ceasefire appeal would only begin "in the course of next week".

The US supports Israel's view that the violence can only end when the Hizbullah militia is disarmed, or at least removed from Israel's border. "We cannot return to the status quo ante," Ms Rice told a press conference. Lebanon had to have "one authority and one gun".

Echoing this, Mrs Beckett said that even if the gathering had called for ceasefire now, it is likely it would have been impossible to implement it under the current conditions. "Even if you could get a ceasefire half an hour ago, you would probably be back in hostilities in a few days," she said.

The conference agreed on the need for an international force in Lebanon that "should be urgently authorised under a UN mandate" to support the Lebanese armed forces in establishing security. But there was a hint of scepticism from the UN secretary general, Kofi Annan, who described it as a force "that may eventually be sent to the region". No participants pledged troops. An EU official said France and Spain may send troops depending on the mandate and rules of engagement, to be supplemented by forces from Turkey, the Netherlands, Canada, Egypt and Saudi Arabia.

A western diplomat described as "within the range of possibility" a report in the New York Post claiming that Ms Rice would float a two-stage plan for an international force in Lebanon. The first part of the plan would call for 10,000 troops, perhaps from Muslim countries , including Egypt and Turkey, to enter Lebanon as soon as a ceasefire was declared. They would then be replaced by a larger force of up to 30,000 troops after about 90 days.

In an interview before the conference, the French president, Jacques Chirac, ruled out a Nato role in the proposed Middle East security force, saying the alliance is seen as "the armed wing of the west".

With Washington apparently committed to an ambitious plan for a ceasefire only within the framework of a durable settlement, Ms Rice made it clear she was bent on wringing some movement from Syria, saying it had internationally-agreed obligations. "The question is whether Syria intends to exercise these obligations in such a way that it leads to a fully sovereign Lebanon," Ms Rice said.

Mr Annan, who emerged from the talks looking grim-faced, suggested that talks be opened with Iran and Syria. He appealed in vain for the participants to concentrate on a temporary cessation of hostilities so that humanitarian assistance could be provided.

Lebanon's prime minister, Fouad Siniora, made what Ms Rice described an "impassioned appeal" to the summit. "Is the value of human rights in Lebanon less than that of citizens elsewhere?" he asked. "Are we children of a lesser god? Is an Israeli teardrop worth more than a drop of Lebanese blood?"

Mr Siniora also pleaded for an immediate and comprehensive ceasefire. "The more we delay the ceasefire, the more we are going to witness more being killed, more destruction and more aggression against the civilians in Lebanon," he told the press conference. "For the past 15 days, we are being pounded every day. The country is being cut to pieces."

Dr Hossein Haj Hassan, one of Hizbullah's 14 MPs in Lebanon, cast doubt on the idea of an international force. "Israel has just attacked a UN base and killed four staff. If the UN cannot defend its soldiers, how can international forces defend our country?" he told the Guardian. "Hizbullah favours an immediate ceasefire without conditions," he added.

It was also reported last night that Mrs Beckett had talked to Ms Rice about allegations that Prestwick airport in Scotland had been used as a staging post by US planes transporting bunker-busting bombs to Israel last weekend. Mrs Beckett told Channel 4 News: "We will be making a formal protest [to the US] if it appears that that is what has happened."